The basic modern phonograph system uses a flat disk phonograph record with spiral cut grooves. The record is played on a turntable system which spins the phonograph record at constant rotational speed, using a tone arm system mounted on the arm board, plinth, or other structure of the turntable system (hereinafter referred to as the arm board).
The tone arm system configuration in greatest use consists of an arm with a pickup cartridge at one end and a counterweight at the other end, and with a tone arm pivot system (hereinafter referred to as the tone arm pivot) for rotation of the arm with two degrees of freedom, one horizontal, and one vertical. The tone arm pivot is located near the balance point of the pickup cartridge, tone arm proper, and counterweight. The tone arm pivot is supported by a pedestal or column (hereinafter referred to as the tone arm pedestal), which is mounted to the arm board. The invention discussed herein applies to turntables in which the phonograph record lies in an approximately horizontal plane.
Those skilled in the art of phonograph systems are aware of the following:    1. The angle, during playback, between the axis of the playback stylus (hereinafter referred to as the stylus) and a perpendicular to the plane of the phonograph record disk is known as the Stylus Rake Angle (hereinafter SRA). The angle, during recording, between the axis of the cutter and a perpendicular to the plane of the master phonograph record disk is known as the Cutter Rake Angle (hereinafter CRA).    2. The CRA varies from phonograph record to phonograph record.    3. Best playback occurs when the SRA is close in value to the CRA associated with the phonograph record being played.    4. It is desirable to have a means to easily adjust the SRA to minimize playback signal distortion. It is even more desirable to have a means to easily adjust the SRA while the phonograph record is playing, to allow audible optimization of the perceived quality of the sound.    5. It is possible to produce desired changes in the SRA by raising or lowering the tone arm pedestal, relative to the arm board, by various means.    6. SRA adjustment means provided by the prior art to raise and lower the tone arm pedestal have one or more of the following attributes: a) time consuming to adjust, b) difficult to adjust precisely, c) impossible to adjust with the phonograph record in play, d) require the tone arm system to be mechanically connected to the arm board, or e) use a screw driven elevator column with its vertical axis offset substantially from a vertical axis passing through the center of the tone arm pivot.    7. One prior art means of raising the tone arm pedestal height is the placement of shims under the tone arm pedestal. This means is time consuming to adjust, is difficult to adjust precisely, is impossible to adjust with the phonograph record in play, and requires the tone arm to be mechanically connected to the arm board.    8. Another prior art means of raising the tone arm pedestal is the use of a collar attached to the arm board, through which a vertical pedestal mounting stud passes, said pedestal mounting stud emanating from the tone arm pedestal bottom. The pedestal mounting stud is held in the collar by one or more set screws operating in one or more threaded radial holes through the collar. This means is time consuming to adjust, is difficult to adjust precisely, is impossible to adjust with the phonograph record in play, and requires the tone arm to be mechanically connected to the arm board.    9. Another prior art means of raising the tone arm pedestal uses a pair of nuts running on a threaded vertical pedestal mounting stud emanating from the tone arm pedestal bottom and received by a mounting hole in the arm board. The arm board is trapped between the two nuts, holding the pedestal mounting stud perpendicular to the arm board. In some cases the upper nut is made with a thin wall received by the mounting hole in the arm board, allowing the nut threads to occupy the thickness of the arm board, with a thin flange on top of the upper nut to bear on the arm board upper surface, thereby reducing the minimum height addition the upper nut imparts to the tone arm pedestal. This means is time consuming to adjust, is impossible to adjust with the phonograph record in play, and requires the tone arm to be mechanically connected to the arm board.    10. Another prior art means of raising and lowering the tone arm pedestal uses a screw driven elevator means which is laterally displaced a substantial amount from the vertical axis of the tone arm pivot. This means is complicated and expensive to produce, and requires the tone arm to be mechanically connected to the arm board. Because of its eccentric mounting, the elevator means a) interferes with the reduction of vibration at the interface between the tone arm and the arm board, and b) experiences increased frictional drag from horizontal reactions associated with eccentricity of the elevator means.    11. Another prior art means to produce changes in the SRA is by changing shims between the pickup cartridge and the tone arm. The pickup cartridge may be shimmed parallel or at an angle to the pickup cartridge mounting surface provided by the tone arm system. This method of changing SRA is time consuming to adjust, requiring a complete and exacting realignment of the pickup cartridge each time the shims are changed. Using this method It is impossible to adjust SRA with the phonograph record in play.    12. Another prior art means to produce changes in the SRA is by changing the thickness of the turntable mat between the platter and the phonograph record. This means requires storage of alternative turntable mats, is difficult to adjust precisely, is impossible to adjust with the phonograph record in play, and requires the use of a turntable mat, which some users consider undesirable.
The SRA is closely associated with the angle between the phonograph pickup cantilever and the plane of the phonograph record, said angle commonly called the Vertical Tracking Angle (hereinafter VTA). Changes in the SRA are accompanied by changes in the VTA. In common parlance, when one raises and lowers the tone arm pedestal to change the SRA, one is said to be adjusting the VTA. Because the term “VTA adjustment” is in more common use than the term “SRA adjustment,” the title of the invention refers to a “Vertical Tracking Angle Adjustment System.”
Those skilled in the art of phonograph systems are also aware that:    1. Mechanical vibrations originating in the oscillation of the stylus travel through the pickup cartridge, the tone arm proper, the tone arm pivot, and the tone arm pedestal, to the arm board, where they can be reflected or transferred back into the arm and picked up in delayed manner by the pickup cartridge, blurring the signal and the perceived sound.    2. Decoupling the tone arm pedestal from the arm board, through reduced connection force between the tone arm pedestal and the arm board can reduce transfer of vibrations from the tone arm system to the arm board, and back to the tone arm system, thereby improving the quality of the signal and of the perceived sound.
Further, those skilled in the art of phonograph systems are aware that:    1. With the tone arm connected to an arm board in accordance with prior art, performing adjustments or maintenance on a pickup cartridge or tone arm system is difficult and time consuming.    2. With the tone arm connected to an arm board in accordance with prior art, removing the tone arm system from a turntable or arm board is difficult and time consuming,
As old as the phonograph is, many current observations on audiophile phonograph related web sites lament the fact that the best sound can only be achieved when the VTA is easily adjustable with the phonograph record in play, and that only very expensive tone arm systems offer VTA adjustment while the phonograph record plays.
The invention discussed herein provides a fresh approach to VTA adjustment and offers a new, simple, and low cost way to construct a VTA adjuster that functions with the phonograph record in play. The low cost VTA adjustment methods currently available do not work with the phonograph record in play, and in most cases require the tone arm system to be disconnected from the turntable system, or the pickup cartridge to be removed from the tone arm, to perform VTA adjustments. These methods are almost hopelessly clumsy to use.
Further, the invention discussed herein provides additional advantages of 1) decoupling the tone arm system from the arm board, which eliminates the connecting force, improving damping of tone arm vibrations, 2) allowing a damping washer to be easily added to or removed from the interface between the tone arm system and the turntable system, for tailoring of the perceived sound, and 3) allowing the tone arm to be easily removed from and installed into the arm board, allowing easy maintenance and adjustments.